The Element.nextElementSibling read-only property returns the element immediately following the specified one in its parent's children list, or null if the specified element is the last one in the list.

A Element object, or null.

<div id="div-01">Here is div-01</div>
<div id="div-02">Here is div-02</div>

<script>
  let el = document.getElementById("div-01").nextElementSibling;
  console.log("Siblings of div-01:");
  while (el) {
    console.log(el.nodeName);
    el = el.nextElementSibling;
  }
</script>

This example outputs the following into the console when it loads:

Siblings of div-01:
DIV
SCRIPT

• Element.previousElementSibling